300 Blk reloading

timelinex

Gunny Sergeant
Full Member
Minuteman
  • May 7, 2011
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    Scottsdale,Az
    I'm getting into a SBR 300blk AR and plan on only using subsonic through it. It's most likely going to be the 9" aac upper.

    Generally I use redding type s sizing dies with a forster competition seating die. Is that a good combo for this caliber as well? More importantly, do I need a dedicated 300 Blk seater or does it use a 308 or 223 seater anyways.

    My other question is components. What are good subsonic bullets, powders, brass and primers for the cartridge? The cartridge won't be for longer range than the subsonic effective range which is around 300ish. So price and inherent accuracy is more important than maximum BC.

    thanks
     
    I just loaded up some Sierra 220gr round nose the other day with AA1680 and they ran great. The only hitch is that they don't fit in a Pmag, but fit USGI mags just fine. The load was quiet with good accuracy. I was not shooting groups, but it was great on steel. I use Lee dies with the factory crimp die on this round.
     
    You will need 300 BO dies to reload. I am sure you can find match dies but I don't think they will help all that much.


    Both redding and forster making dies for the 300 AAC. Are you saying you recommend I just get run of the mill 'inexpensive' dies? I've always loaded everything to the best precision I can, but I recognize that this isn't exactly a precision rifle. Old habits die hard!

    I'm just wondering why the 308 seater won't work. It's wide enough to accept the 300blk case and the seating stem is perfectly sized for the 30 cal bullets. Obviously a 223 shellholder will be used, so the casing will be centered.
     
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    I have the lee 3 die set with the crimp die included. Mid south shooters supply had a special on them here recently. May want to check them out.
     
    I suggest that if you are loading 300 BO for a 9" AAC upper and shooting sub-sonic, then your engagement ranges will be limited to 200 yds or so. Sure, you can spend more money on nice dies but I should think that a standard set of 300 BO dies will work just fine considering the short far case and thick necks.

    If it was the end of the world, yes you could use a .308 seating due to get a bullet in the case; you could also use a clamp and a hammer to seat a bullet. The case would be completely unsupported provided you could get the seating stem low enough to make the .308 seating die work. A new set of hornady dies will run you about 35.00 and a lee 3 die set about the same. Its money well spent.
     
    I use 208 amaxs over 1680 and CCI 400. Buy a good set of dies and load away. Don't try to use improper tools when reloading. Would you use whatever powder you had on hand because it will probably work?

    I use Hornady dies for blackout. It's really dangerous to get in the mentality of trying to cut corners when it comes to reloading. And if accuracy is your main concern, bullet seating is very important.

    Oh and I've loaded subsonics with 220 SMKs and they fit in a pmag just fine.
     
    I just loaded up some Sierra 220gr round nose the other day with AA1680 and they ran great. The only hitch is that they don't fit in a Pmag, but fit USGI mags just fine. The load was quiet with good accuracy. I was not shooting groups, but it was great on steel. I use Lee dies with the factory crimp die on this round.


    I use this only with 220 SMK's and they do fit in the pmag.

    The lee crimp die is also a great value. It is cheap...but until it doesn't work I have no reason to try anything more expensive. It has actually worked better for me than RCBS's crimping dies.
     
    For subs, I have used Sierra 220gr MK bullets in both converted cases and once-fired Remington 300 BLK cases. Primer used was Federal GM205MAR. The match primer wasn't necessary, just what I had at the time.

    RCBS also makes a 300 BLK die set
     
    I use this only with 220 SMK's and they do fit in the pmag.

    The lee crimp die is also a great value. It is cheap...but until it doesn't work I have no reason to try anything more expensive. It has actually worked better for me than RCBS's crimping dies.

    So I take it that you crimp the bullets? May I ask why? I thought crimping is mostly unnecessary for rifle loads as long as you have proper neck tension.

    Also, I thought for subsonic loading, crimping is even frowned upon
     
    For subs I've been loading 208 A-max's over AA1680 and they run well in pmags. For supers I've been loading 125 gr Speer TNT's and 125 gr Nosler BT's for deer hunting.

    I've been using Hornady dies without issue and honestly I see zero need to crimp 300 blk because of the thickness of the case on the necks, I've had to pull a couple and they definitely aren't loose. I went with Hornady dies since that's all I could find at the time, and they've done just fine. If it makes you feel better get a set of Forster or Redding's but I surely wouldn't drop the money for a match/micrometer seating die for that caliber, or bushing dies for that matter. I just don't think you'll realize the benefit from them, especially in an AR, and shooting subs, a bolt gun maybe but also at the ranges where it's relevant, I wouldn't bother.

    For Brass, I have a friend that has a dillon 1050 set up for converting 556 brass and I buy it from him. I've made some of my own, but honestly it's such a PITA that it's worth it to just buy it from him. If you can find actual 300 blk brass for a reasonable price, by all means go for it.
     
    I crimp anything going through an ar. I haven't had any problems...but there may be something I don't know.

    This is also my line of thought with respect to crimping. For subs, I usually only do a light crimp though. I'll go a little heavier on supers because some of the lighter .30 cal bullets end up with the start of the ogive pretty close to the case mouth and I'm a little paranoid about any setback spiking chamber pressure.
     
    The Lapua 200gr subsonic bullet is one you should look at. I've been getting 1/4" groups with it out of my 308 DTA at 100yds. I've haven't tried an accuracy test out of my 300AAC yet though, I've only just loaded up some 220gr SMKs. I only have an Aimpoint on the 300AAC so it's hard to compare.
     
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    No doubt about it they are easier/quicker to adjust and that is convenient if the cash outlay isn't an issue to you.

    I just personally don't see it a necessity for that cartridge since when I do load for it, I load an assload of one loading on my dillon, and stick it in the closet. When I set up the dillon to load 300 blk, the seating is far easier to set up than the powder measure. I also have reference marks on the seating stem and body that get me really close for each bullet I load in it. I just set it up and mark the stem/body with a sharpie for one bullet, and use a different color sharpie for the next. Works good to get me dialed in on it quickly.

    Either way it's a fun cartridge and relatively easy to load for, there's so many flavors of loadings for it that it's never really dull.
     
    OK, so I looked at all the recommendations and read alot of reviews and I settled on the forster ultra 2 die set. It has the seater I like using and a good sizer. More expensive than lee/rcbs but less than redding.

    SO. Now I have everything but a suitable powder. Anyone have any idea where I can get some aa1680. Looks like its the preferred powder for 300blk subs and 208amax, but its not in stock anywhere!
     
    OK, so I looked at all the recommendations and read alot of reviews and I settled on the forster ultra 2 die set. It has the seater I like using and a good sizer. More expensive than lee/rcbs but less than redding.

    SO. Now I have everything but a suitable powder. Anyone have any idea where I can get some aa1680. Looks like its the preferred powder for 300blk subs and 208amax, but its not in stock anywhere!
    Good luck on the 1680, like I said, it's a unicorn. That's why I was curious on the Norma 200 powder to see if you can use that rather than the 1680 for subs
     
    Thankfully I bought some 1680 when it was in stock about a year ago, for subs it's about as good as it gets, but I haven't seen it in stock for quite a while. I've also been able to get aa5744 to work but not as consistent on the cycling, but with a pistol length, it might get it done for you, especially supressed. (mine is sort of a morphadite between pistol length and carbine, works good but only really likes 1680 for subs) On a side note, it works exceptionally well for supers so if it doesn't get your subs to cycle, you can make some great plinking ammo or hunting ammo with it.

    Some more load info, Sub-Sonic Loads

    make sure and read the notes at the end of the data.

    Also there's a lot of info on the quarterbore forums.
     
    The 300BLKTalk forum also has a ton of load data with people trying a lot of different powders for subs.

    I know that some people have gotten Reloader 7 and H110 to work with subs. Hodgdon lists subsonic load data but I'm not sure if all of the powders listed would provide correct pressures to cycle an AR. I've attempted to use Alliant 2400 but couldn't get my AAC 9" upper to cycle without going supersonic.
     
    Not like that's in Stock anywhere either!
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    Cant find H110 ?
    If you see, Win 296 . Don't forget that Win 296 & H110 is one in the same .

    But if you have to get by till you find the personal & Ideal 'Flavor of your Choice' in Powder . You can damn near get any Powder for Magnum Pistol and work-up a Load .

    also: on the Crimp . always Crimp on the 'Subsonics' & will really tighten-up the groups and help consistency of Vel. shooting out of both AR & Boltaction on the 30-223 .
    For High Velocity Rounds & Boltgun . I dont crimp & Neck-size only . But I always crimp on High Vel. on the AR .
    my favorite Crimp is the Lee Collet crimp .
    .
     
    My other question is components. What are good subsonic bullets, powders, brass and primers for the cartridge? The cartridge won't be for longer range than the subsonic effective range which is around 300ish. So price and inherent accuracy is more important than maximum BC.

    thanks
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    Good Subsonic Vel . Projectiles . I just ran 250 of these and they are fantastic running flawlwess, accurate and GOOD price for banging steel or punching paper .
    Those Poly Jacket shoot real good . My favorite Subsonic Vel. Bullet is Berger 210 VLD's ..BUT.. Now I dont Cringe, when I give a people a full Mag. of these 203 grn. Poly Jackets to burn threw and checkout the Suppressed 30-223 .

    BlackoutBrass.com ? 203gr Projectiles. Suppressor Safe! Cheap 300 Blackout subsonic.
    .
     
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    Good Subsonic Vel . Projectiles . I just ran 250 of these and they are fantastic running flawlwess, accurate and GOOD price for banging steel or punching paper .
    Those Poly Jacket shoot real good . My favorite Subsonic Vel. Bullet is Berger 210 VLD's ..BUT.. Now I dont Cringe, when I give a people a full Mag. of these 203 grn. Poly Jackets to burn threw and checkout the Suppressed 30-223 .

    BlackoutBrass.com ? 203gr Projectiles. Suppressor Safe! Cheap 300 Blackout subsonic.
    .

    Oh wow. That's a great website with great deals. Thank you for that link

    Edit: looking into the company, it looks like they get alot of flak for being unreliable, no delivery and no consensus on if they perform or Crap up the rifle/suppressor
     
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    Oh wow. That's a great website with great deals. Thank you for that link

    Edit: looking into the company, it looks like they get alot of flak for being unreliable, no delivery and no consensus on if they perform or Crap up the rifle/suppressor
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    Hey, ( timelinex ) . I just finished shooting a bag of these bullets . Was a little apprehensive when 1st putting my eyeball on these up close . But I have to admit that I have had nothing but positive results when working-up the final load and shooting them .The accuracy was very good tight and no flyers .
    Bullets Price $$ . Is pretty sweet also for there retail price .
    ( for Me ) . A Cheep priced 200+grn. bullet for .30 cal. AR, subsonic shooting is a 'welcomed change' over my taste for the Berger 210 Vld's . These coated jacket bullets are Definitely meant for just going out and shooting mass rounds banging steel or paper etc. without stinging your Wallet .
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    Was shooting -- 8.5 inch - SS 5R, 8-twist - pistol position gas block - Suppressed.
    My final load data that I settled with to keep . 8.6 grn. Win.296/H110 . 1040-1050 fps Vel. - OAL 2.020 / with Lee Colet Crimp
    I also found myself using less powder than I expected on the Load work-up to get to my desired Vel. . Maybe was bearing surface area or combination that with jacket coating ?
    No problems with Seating the coated bullets in Necks . I just gave a good chamfer and had no burs or dented mouths when Seating . All went smooth and then gave a med. heavy crimp, Not a super hard heavy cam-over .

    I think it is said best to keep Coated Jacket over the lead subsonic Vel./fps . I found that the Coating jacket is tough . ( I Personally think ) It Is more than adequate Gas-Check covering the bullets Base for subsonic Vel FPS .. So not adding Lead dust to my Suppressors Blast baffle when firing them .
    Coating also is 'Surprisingly' pretty clean in the Bore . Also real positive seal on the Land/Groove and also on the bullets base .
    .. THIS ---> .. It's not like Shooting volumes of subsonic Vel. Bullets is friction and heat magnet . (imho) guessing from what I see . This bullet jacket coating, It is acting as somewhat a lube as it seems to not add friction in the Bore with also not to leave it dirty with bullets coating .. I found it was a breeze to easy clean with running a dry Patch down the Bore also with see No Jacket Coating on he patches when I was eye-balling them .

    I REALLY Checked this Bullet Out . I can be a picky bastard sometimes with what I shove in my shooters . I dont beat around the bush, If I think something is shit, I will just come out & say so .
    The Coating over the lead is tough bond but remains slightly flexible . I even took a couple and put them on the concrete floor and smacked them a few times with a 2-Lb. sledge hammer . I could not get the Coating bond to crack or break free from the Lead . Even when the hammer flattened the Lead to a sharp edge . Pretty amazing and tough stuff . I Will be shooting more of these .
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